The technique of electrically connecting terminals of electronic parts by joining them by the use of a joining material is known. For example, solder which contains one or more kinds of components is used as a joining material. For example, the technique of mounting a semiconductor element or a semiconductor package over a board, such as a printed board, by the use of solder bumps is known.
Japanese Laid-open Patent Publication No. 2002-239780
Japanese Laid-open Patent Publication No. 2007-242783
A joining failure, such as a crack, peel, or disconnection, may occur in a joining portion between terminals of electronic parts due to impact from the outside or a thermal stress created by heat generated by the electronic parts or heat applied to the electronic parts.